[Influence of environmental tobacco smoke on characteristics of childhood asthma].

INTRODUCTION: We compared characteristics of asthma in children from smoking and non-smoking families. OBJECTIVE: To examine if there was any difference in asthma in children exposed and not exposed to environmental tobacco smoke (ETS). METHODS: We examined 231 asthmatic children and their parents. According to the questionnaire and carbon monoxide (CO) values in exhaled air measured by Smokerlyzer, we divided the children in two groups: children from smoking and children from non-smoking families. We compared birth weight, birth length, the occurrence of the first broncho-obstruction, the number of respiratory infections and exacerbations per year, asthma severity, the number of hospitalizations, total IgE, Skin prick test and allergic manifestations. We examined the influence of parental educational level on smoking behaviour and how much money a smoking family spent on cigarettes. RESULTS: The children's average age was 10.6 years, there were 49% of boys and 51% of girls. We had 77% of smoking families, 45.9% of active smoking mothers and 51% of active smoking fathers. Smoking was more common among lower educated parents. A smoking family spent 7.3% of the family budget on cigarettes. The children from smoking families had more allergic manifestations. The children of smoking mothers had more respiratory infections (without a statistic difference in the second and third year) and more asthmatic exacerbations with a statistic difference after the third year. With parents who smoked, children had more severe asthma. There was no statistical difference in the following: birth weight, birth length, Skin prick test, total IgE, the first wheezing episode and the number of hospitalizations. However, in the group of 26 children with exhaled CO values higher than 6 ppm, birth weight was lower (3250 g vs. 3550 g), the first wheezing episode occurred earlier (2 years vs. 3.7 years) and total IgE was higher (702 IU/ml vs. 563 IU/ml) by more than two normal ranges (60 IU/ml). CONCLUSION: It is necessary to protect children with asthma from ETS because it has a negative impact on their illness.

[Impact of inaccuracy of peak flowmeters with Wright scale on asthma severity assessment in children].

INTRODUCTION: Measurement of daily variability of peak expiratory flow (PEF) is widely accepted as an objective method to assess asthma severity. Recent investigations have proved nonlinearity of original Wright scale of peak flowmeter. All country members of European Union have been obliged to implement a new scale according to standard EN 13826 since 2005. This study examined whether the correction of PEF values for the inaccuracy of the scale would affect asthma management based on their daily variability. MATERIAL AND METHODS: We analyzed PEF values (2352) in 34 children, aged 5-16, during 3-5 weeks of monitoring in order to establish the diagnosis of asthma by using peak flowmeters with Write scale. The correction of measured values for inaccuracy was managed with original Dr. M. Miller's predictive equation. The daily variability of PEF (amplitude percent mean) up to 20% was considered as "normal", 20-29.9% as "raised", and 30% and above as "high ". The assessment of daily variability was performed before and after correction. RESULTS: There was no significant change in the number of days with airway lability as regarding the assessed whole study group (p = 0.475). However, 22 (64.7%) of children had at least one false clinical message about daily variability during the monitoring. It was overestimated in 12 (7%) days in younger (6.6 +/- 0.8 years) or of shorter stature (122.6 +/- 3.6 cm) and underestimated in 13 (4%) days in older (11.1 +/- 2.7) or taller ones (150.9 +/- 12.5 cm) (p < 0.001). CONCLUSION: Usage of peak flowmeters with Wright scale may lead to an error in asthma severity assessment based on daily variability of PEF. It may cause overtreatment or undertreatment of asthmatic children.

[Effects of nonlinear error correction of measurements obtained by peak flowmeter using the Wright Scale to assess asthma attack severity in children].

INTRODUCTION: Monitoring of peak expiratory flow (PEF) is recommended in numerous guidelines for management of asthma. Improvements in calibration methods have demonstrated the inaccuracy of original Wright scale of peak flowmeter. A new standard, EN 13826 that was applied to peak flowmeter was adopted on 1st September 2004 by some European countries. Correction of PEF readings obtained with old type devices for measurement is possible by Dr M. Miller's original predictive equation. OBJECTIVE: Assessment of PEF correction effect on the interpretation of measurement results and management decisions. METHOD: In children with intermittent (35) or stable persistent asthma (75) aged 6-16 years, there were performed 8393 measurements of PEF by Vitalograph normal-range peak flowmeter with traditional Wright scale. Readings were expressed as percentage of individual best values (PB) before and after correction. The effect of correction was analysed based on The British Thoracic Society guidelines for asthma attack treatment. RESULTS: In general, correction reduced the values of PEF (p < 0.01). The highest mean percentage error (20.70%) in the measured values was found in the subgroup in which PB ranged between 250 and 350 l/min. Nevertheless, the interpretation of PEF after the correction in this subgroup changed in only 2.41% of measurements. The lowest mean percentage error (15.72%), and, at the same time, the highest effect of correction on measurement results interpretation (in 22.65% readings) were in children with PB above 450 l/min. In 73 (66.37%) subjects, the correction changed the clinical interpretation of some values of PEF after correction. In 13 (11.8%) patients, some corrected values indicated the absence or a milder degree of airflow obstruction. In 27 (24.54%) children, more than 10%, and in 12 (10.93%), more than 20% of the corrected readings indicated a severe degree of asthma exacerbation that needed more aggressive treatment. CONCLUSION: Correction of PEF values obtained by peak flowmeters with traditional Wright scale shows a possibility of overtreatment in younger or short stature children and undertreatment in older or taller ones if we use old type of metres. The correction of peak flowmeter for non-linear error is a prerequisite in the application of asthma guidelines in PEF measurements.

[Influence of smoking habit on respiratory function in young asthmatics: follow-up study from 16-30 years of age].

INTRODUCTION: Smoking habit of 54 asthmatics was followed for 15 years. OBJECTIVE: To examine if there was any difference of lung function tests between smoking and nonsmoking young asthmatics. METHOD: Based on questionnaires, clinical examinations, lung function tests and skin prick tests, 54 adolescents with asthma were separated out of 1134 pupils of one Belgrade high school. They were followed-up till the age of 30. RESULTS: 62.9% of subjects were females and 37.1% were males. Average age at the beginning was 16.3 and 29.6 at the end of study. In 13.0% of subjects, the asthma manifested in the first year of life, in 72.2% between 2-6 years of age and in 14.8% of our subjects, the asthma developed after 7th year. The symptoms of asthma in last 12 months were present in 54.8% of our subjects at the age of 16, compared to 77.8% of asthmatics with asthma symptoms at the age of 30. Percent of smokers increased cumulatively from 16.7% at the beginning of study up to 57.5% upon its completion. Number of cigarettes increased from 7.5% to 16.5% cig/day in a smoker from the adolescent period until the end of study, with no difference in relation to sex. Average duration of smoking experience was 11.5 years, no difference in relation to gender. Values of VC, FVC, FEV1, PEF and MEF75 were always lower in asthmatics-smokers, but with no statistical difference. Tiffeneau index, MEF25 and MEF50 were statistically lower in the smoking group at the age of 30 compared to their values at the age of 21. CONCLUSION: Smoking does affect lung function of asthmatics that started to smoke and Tiffeneu index, MEF25 and MEF50 were statistically lower as early as at the age of 30.